Relativity

From the age of Galileo until the early years of the 20th century, scientists grappled with seemingly insurmountable paradoxes inherent in the theories of classical physics. With the publication of Albert Einstein’s “special” and “general” theories of relativity, however, traditional approaches to solving the riddles of space and time crumbled. In their place stood a radically new view of the physical world, providing answers to many of the unsolved mysteries of pre-Einsteinian physics.
Acclaimed as the pinnacle of scientific philosophy, the theories of relativity tend to be regarded as the exclusive domain of highly trained scientific minds. The great physicist himself disclaimed this exclusionary view, and in this book, he explains both theories in their simplest and most intelligible form for the layman not versed in the mathematical foundations of theoretical physics.
In addition to the theories themselves, this book contains a final part presenting fascinating considerations on the universe as a whole. Appendices cover the simple derivation of the Lorentz transformation, Minkowski’s four-dimensional space, and the experimental confirmation of the general theory of relativity. Students, teachers, and other scientifically minded readers will appreciate this inexpensive and accessible interpretation of one of the world’s greatest intellectual accomplishments..

General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1915. It is the current description of gravitation in modern physics. General relativity generalises special relativity and Newton’s law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or spacetime. In particular, the curvature of spacetime is directly related to the four-momentum (mass-energy and linear momentum) of whatever matter and radiation are present. The relation is specified by the Einstein field equations, a system of partial differential equations. Einstein’s theory has important astrophysical implications. For example, it implies the existence of black holes-regions of space in which space and time are distorted in such a way that nothing, not even light, can escape-as an end-state for massive stars. There is evidence that such stellar black holes as well as more massive varieties of black hole are responsible for the intense radiation emitted by certain types of astronomical objects such as active galactic nuclei or microquasars.